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<title>RESET</title>
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<h1><a name="SQL-RESET"></a>RESET</h1>
<div class="REFNAMEDIV"><a name="AEN53184"></a><h2>名称</h2>RESET&nbsp;--&nbsp;把一个运行时参数重置为缺省值</div>
<a name="AEN53187"></a>
<div class="REFSYNOPSISDIV"><a name="AEN53189"></a><h2>语法</h2>
<pre class="SYNOPSIS">RESET <tt class="REPLACEABLE"><i>configuration_parameter</i></tt>
RESET ALL</pre>
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<div class="REFSECT1"><a name="AEN53192"></a><h2>描述</h2>
<p><tt class="COMMAND">RESET</tt> 将运行时参数恢复为缺省值。<tt class="COMMAND">RESET</tt> 是下面语句的一个变种</p>
<pre class="SYNOPSIS">SET <tt class="REPLACEABLE"><i>configuration_parameter</i></tt> TO DEFAULT</pre>
<p>请参考 <a href="sql-set.html"><i>SET</i></a> 命令获取详细信息。</p>
<p>缺省值是变量可以拥有并且在当前会话中没有用 <tt class="COMMAND">SET</tt> 设置过的值。这个数值的实际源头可能是编译时的缺省：配置文件、命令行开关、针对每个数据库或每用户的缺省设置。参阅<a href="runtime-config.html">章17</a>获取细节。</p>
<p>参阅 <tt class="COMMAND">SET</tt> 手册页获取有关 <tt class="COMMAND">RESET</tt> 的事务行为的细节。</p>
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<div class="REFSECT1"><a name="AEN53206"></a><h2>参数</h2>
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<dt><tt class="REPLACEABLE"><i>configuration_parameter</i></tt></dt>
<dd><p>运行时参数的名称，请参考 <a href="sql-set.html"><i>SET</i></a> 语句获取详细说明。</p></dd>
<dt><tt class="LITERAL">ALL</tt></dt>
<dd><p>把所有运行时参数设置为缺省值</p></dd>
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<div class="REFSECT1"><a name="AEN53220"></a><h2>例子</h2>
<p>把 <tt class="VARNAME">geqo</tt> 配置变量设为其缺省值：</p>
<pre class="SCREEN">RESET geqo;</pre>
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<div class="REFSECT1"><a name="AEN53225"></a><h2>兼容性</h2>
<p><tt class="COMMAND">RESET</tt> 是 PostgreSQL 扩展</p>
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